This application claims the priority of JP 11-364413, file Dec. 22, 1999, the disclosure of which is expressly incorporated by reference herein.
1. Field of the Invention
The present invention relates to an intraocular surgical apparatus for use in a surgical operation for treating, e.g., cataract.
2. Description of the Related Art
In recent years, for treatment of eye diseases such as cataract, a surgical operation is often carried out to replace the affected crystalline lens in the eye of the subject with an intraocular lens (artificial crystalline lens). In this respect, as an operation for extirpating such an affected part as the crystalline lens, there is known the ultrasonic emulsifying aspirating operation (KPE) for applying ultrasonic waves to the affected part, e.g., crystalline lens, for pulverizing (emulsifying) the part and simultaneously aspirating and discharging the pulverized part to the outside.
A typical apparatus for use in such an ultrasonic emulsifying aspirating operation is shown in FIG. 4. The apparatus includes a handpiece 3 having an introduction tube 1 for introducing perfusate (artificial aqueous humor) C into the closed intraocular affected part B and a discharge tube 2 for discharging the emulsified affected part together with the perfusate C. A perfusate feed passage D connected to the introduction tube 1 incorporates a perfusate reservoir E capable of feeding the perfusate C with a predetermined rest liquid head pressure (h). A discharge passage G connected to the discharge tube 2 of the handpiece 3 incorporates a suction pump H for controlling the operation of a switch valve F of the feed passage D to open the valve F in association with an aspirating operation or to close it in association with stopping of the aspirating operation.
When operating an apparatus constructed as described above, an outlet opening 1B of the introduction tube 1 and an aspiration opening 2A of the discharge tube 2 of the handpiece 3 are inserted together into the closed intraocular affected part B through a small access incision made in the cornea or sclera of the eye to be treated.
Then, ultrasonic waves are applied to the affected part, such as a crystalline lens, for gradual emulsification. At the same time the emulsified part is aspirated and discharged to the outside by the suction force of the suction pump H. During this step, the switch valve F incorporated in the perfusate feed passage D is opened in response to the operation of the suction pump H. Open switch valve F allows the introduction, in association with the sucking action of the pump, of fresh perfusate C into the intraocular affected part B via the introduction tube 1. The amount of fresh perfusate C introduced into the intraocular affected part B corresponds to the amount of material aspirated and discharged from the perfusate reservoir E. This balances the flow rate of perfusate and the suction force of the suction pump.
However, as illustrated in FIG. 5, it sometimes happens that the introduced part may be momentarily stuck at the aspiration opening 2A of the discharge tube 2 and then suddenly released therefrom to be drawn toward the discharging side. In the case of such an excessive aspiration phenomenon, because the perfusate feed passage D provides certain passage resistance and the outflow rate of the perfusate C from the outlet opening 1B of the introduction tube 1 is fixedly governed by the effect of free-fall, the balance between the inflow amount from the introduction tube 1 and the outflow or discharge amount from the discharge tube 2 is lost, with the latter exceeding the former. This leads to momentary abnormal pressure reduction and development of negative pressure within the closed intraocular affected part B compared with a normal pressure in the case of a normal operation. The negative pressure may result in a so-called micro-collapse phenomenon characterized by reduction in the content volume of the eyeball and the anterior chamber. In an extreme case, such a micro-collapse phenomenon may result in rupture of the posterior capsule or damage in the endothelium camerae anterioris.
Customarily, when a surgeon notices the possibility of such a phenomenon, the surgeon will expediently adjust the amount of ultrasonic waves and/or the aspiration amount in such a manner as to avoid it. However, in order for the surgeon to be able to do so, they need a good amount of practice with animal or artificial eyes for training as well as a considerable amount of actual experience in the surgery.
The present invention pertains to the above-described state of the art. The primary object of the invention is to provide an improved intraocular surgical apparatus which effectively prevents occurrence of the micro-collapse phenomenon in the eyeball and the anterior chamber in the event of abnormal pressure reduction in the closed intraocular affected part due to momentary clogging of the affected part at, e.g., the inlet opening of the discharge tube and subsequent sudden movement thereof toward the discharging side.
For fulfilling the above-noted object, according to one aspect of the present invention, an intraocular surgical apparatus is provided, comprising:
an introduction tube for introducing perfusate into a closed intraocular affected part;
a discharge tube for discharging the affected part together with the perfusate;
a perfusate feed passage connected to the introduction tube, the perfusate feed passage incorporating a perfusate reservoir capable of feeding the perfusate with a predetermined rest liquid head pressure, and a control valve for controlling the amount of perfusate to be fed from the perfusate reservoir to the introduction tube; and
a discharge passage connected to the discharge tube, the discharge passage incorporating a suction pump;
wherein the perfusate feed passage further incorporates, at a passage portion thereof from the control valve to an outlet opening of the introduction tube, a pressure-reduction compensating means capable of feeding a supplementary amount of perfusate into the closed intraocular affected part through a supplementing passage having a smaller passage resistance than the perfusate feed passage in the event of and in association with abnormal pressure reduction inside the affected part.
With the above-described construction, in the event of abnormal pressure reduction in the closed intraocular affected part due to momentary clogging of the affected part (at, e.g., the inlet opening of the discharge tube) and subsequent sudden release and movement thereof toward the discharging side, in operative association with this pressure reduction, the pressure-reduction compensating means can supply, through the supplementing passage, a supplementary amount of perfusate to the affected part in order to compensate for the pressure reduction. Accordingly, occurrence of micro-collapse in the eyeball and the anterior chamber can be effectively prevented, so that the surgical operation may take place in a safe and reliable manner.
In the above construction, the pressure-reduction compensating means is provided midway to the perfusate feed passage. Since the passage resistance becomes smaller closer to the inlet opening of the discharge tube, it is preferred that the pressure-reduction compensating means be provided at a position near the inlet opening of the discharge tube. It is also to be noted that the control valve incorporated within the perfusate feed passage can be a variable-flow control valve instead of a switch valve.
According to one preferred embodiment of the present invention, the pressure-reduction compensating means includes a supplementary perfusate reservoir storing a portion of the perfusate flowing within the perfusate feed passage and acting as a supplementing passage, and a gas reservoir for reserving gas compressed under the predetermined rest liquid head pressure of the perfusate reservoir. With this construction, in the event of abnormal pressure reduction in the closed intraocular affected part due to momentary clogging of the affected part (at, e.g., the inlet opening of the discharge tube) and subsequent sudden release and movement thereof toward the discharging side, in association with this reduction, expansion of the gas reserved in the gas reservoir under the compressed state occurs, which expansion causes an immediate reverse flow of the perfusate portion in the supplementing perfusate reservoir, as the supplementing passage of the pressure-reduction compensating means has a smaller passage resistance than the perfusate feed passage, into the intraocular affected part. Therefore, the construction with this additional feature can prevent occurrence of-the micro-collapse phenomenon in the eyeball and the anterior chamber more reliably and can ensure an even more reliable and safer surgical operation.
According to a further preferred embodiment of the invention, the introduction tube and the discharge tube are provided in a handpiece which includes an ultrasonic-wave-generating means capable of applying ultrasonic waves focused in the vicinity of the inlet opening of the discharge tube. With this feature, the affected part is emulsified with the ultrasonic waves and this emulsified part is discharged together with the perfusate, in the event of abnormal pressure reduction in the closed intraocular affected part due to momentary clogging of the affected part (at, e.g., the inlet opening of the discharge tube) and subsequent sudden release and movement thereof toward the discharging side. Then, in association with or triggered by this pressure reduction, expansion of the gas reserved in the gas reservoir under the compressed state occurs, which expansion causes immediate reverse flow of the perfusate portion in the supplementing perfusate reservoir, because the supplementing passage of the pressure-reduction compensating means has a smaller passage resistance than the perfusate feed passage, into the intraocular affected part. Therefore, construction with this additional feature can prevent occurrence of micro-collapse in the eyeball and the anterior chamber more reliably. Hence, this construction can be employed in, e.g., the ultrasonic emulsifying aspirating operation (KPE) for significantly improving its safety and reliability.
According to a further embodiment of the invention, the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means are constructed in the form of a single flexible continuous tube. This construction can improve the maneuverability of the apparatus so as to not interfere with the surgical operation and can improve also the handling of the apparatus. Moreover, the construction facilitates attachment of the pressure-reduction compensating means to an existing system such as a system used for the ultrasonic emulsifying aspirating operation. This attachment requires only a minor modification of the system, such as use of a connector, e.g., a branch-joint tube, capable of connecting the tube to the inlet opening of the introduction tube of the handpiece. The readiness of the attachment will contribute to widespread use of the apparatus of the invention.
According to a further embodiment of the invention, the flexible tube constituting the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means is made of silicone.
Silicone material has the advantage of high resistance against chemical influence. Silicone is advantageous also in that it can be reused after, e.g., sterilization. Moreover, if the silicone is translucent, then the translucence provides visibility from the outside of the supplementary perfusate reservoir and the gas reservoir disposed inside, thus facilitating preparation for a surgical operation. Further, if a mark is provided between the supplementary perfusate reservoir and the gas reservoir, this will help accuracy in the preparation, thus further improving the handling of the apparatus.
According to a further embodiment of the invention, the tube constituting the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means is provided at an upper end of the gas reservoir, and is opened and closed by an opening-closing means. With this feature, the leading end of the tube constituting the pressure-reduction compensating means is raised and then closed by the opening-closing means. Then, a switch valve incorporated in the perfusate feed passage is opened to allow introduction of the perfusate from the perfusate reservoir into the tube with the predetermined rest liquid head pressure applied to this feed passage, thereby forming the supplementary perfusate reservoir. At the upper portion of the supplementary perfusate reservoir, the gas reservoir may then be formed for reserving gas compressed under the predetermined rest liquid head pressure of the perfusate reservoir via the supplementary perfusate present in the supplementary perfusate reservoir. That is, the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means may be readily formed by using an ordinary tube. Moreover, the preparation of the pressure-reduction compensating means may be performed quickly.
According to a further embodiment of the invention, the tube constituting the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means is detachably connected and in communication with the perfusate feed passage connected to the introduction tube. With this feature, the detachability of the tube facilitates the assembly and disassembly of the apparatus for storage after use. The detachability also facilitates sterilization and replacement of the apparatus or its parts when needed. Furthermore, by detaching the tube and then attaching a plug instead, any other conventional surgical operation can be effected. In this manner, different intraocular surgical apparatuses may be used interchangeably, depending on the need.
According to a further embodiment of the invention, the tube constituting the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means has an inner diameter substantially equal to that of a tube constituting the perfusate feed passage. With this feature, advantages may be obtained. If one of the tubes has a different diameter from the diameter of the other tube, the perfusate will flow from the large-diameter tube into the small-diameter tube, hence providing a resistance at the transition region. By using tubes with equal diameters, such resistance does not occur and the apparatus can cope with the pressure variation, i.e., reduction from the normal pressure at the time of normal operation, in the closed intraocular affected part, in a more reliable and speedy manner.
According to a further embodiment of the invention, the gas reservoir of the pressure-reduction compensating means is charged with inert gas. With this feature, the supplementing perfusate reservoir is placed in contact with a non-reactive gas atmosphere, allowing sterilization. This further adds to the reliability and the safety of the surgical operation.
According to an embodiment of the pressure-reduction compensating means of the intraocular surgical apparatus relating to the present invention, the pressure-reduction compensating means, when provided at a passage portion of the perfusate feed passage from the control valve to an outlet opening of the introduction tube, is capable of feeding a supplementary amount of perfusate into the closed intraocular affected part through a supplementing passage having a smaller passage resistance than the perfusate feed passage in the event of and in association with abnormal pressure reduction inside the affected part. With this feature, when the pressure-reduction compensating means is provided midway to the perfusate feed passage, in the event of abnormal pressure reduction in the closed intraocular affected part due to momentary clogging of the affected part (at, e.g., the inlet opening of the discharge tube) and subsequent sudden release and movement thereof toward the discharging side, in association with this reduction, the pressure-reduction compensating means is capable of feeding a supplementary amount of perfusate into the closed intraocular affected part through a supplementing passage having a smaller passage resistance than the perfusate feed passage. Therefore, the construction can prevent occurrence of the micro-collapse phenomenon in the eyeball and the anterior chamber.
According to an embodiment of the tube constituting the pressure-reduction compensating means set forth in the present invention, a branch-joint tube is provided for branch-connecting a base end of the tube to the perfusate feed passage as a member for forming the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means inside the tube as being connected and in communication with the perfusate feed passage. With this feature, in the attachment of the pressure-reduction compensating means to an existing system, such as a system used for the ultrasonic emulsifying aspirating operation, because the branch-joint tube is provided in advance as being connected to the base end of the tube constituting the pressure-reduction compensating means, this attachment can be done easily by connecting this branch-joint tube to the inlet opening of the introduction tube of the handpiece. This readiness of the attachment will contribute to widespread use of the apparatus of the invention.
According to a further embodiment of the tube constituting the pressure-reduction compensating means of the present invention, an opening-closing means for opening and closing the leading end of the tube formed at the upper end of the gas reservoir is provided as a member for forming the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means inside the tube as being connected and in communication with the perfusate feed passage. With this feature, the leading end of the tube constituting the pressure-reduction compensating means is raised and then closed by the opening-closing means. Then, a switch valve incorporated in the perfusate feed passage is opened to allow introduction of the perfusate from the perfusate reservoir into the tube with the predetermined rest liquid head pressure applied to this feed passage to form the supplementary perfusate reservoir. At the upper portion of this supplementary perfusate reservoir, the gas reservoir may then be formed for reserving gas compressed under the predetermined rest liquid head pressure of the perfusate reservoir via the supplementary perfusate present in this supplementary perfusate reservoir. That is, the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means may be readily formed by using such very simple construction. The preparation of the pressure-reduction compensating means may be performed quickly.
According to a further embodiment of the tube constituting the pressure-reduction compensating means of the present invention, to form the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means inside the tube being connected and in communication with the perfusate passage, a branch-joint tube is provided. The branch-joint tube branch-connects a base end of the tube to the perfusate feed passage. An opening-closing means for opening and closing the leading end of the tube formed at the upper end of the gas reservoir is provided. With this feature, the tube constituting the pressure-reduction compensating means as being connected and in communication with the perfusate feed passage is raised with its leading end oriented upward. Then, the leading end of this tube is closed by the opening-closing means and a switch valve incorporated in the perfusate feed passage is opened to allow introduction of the perfusate from the perfusate reservoir into the tube with the predetermined rest liquid head pressure applied to this feed passage to form the supplementary perfusate reservoir. At the upper portion of this supplementary perfusate reservoir, the gas reservoir may then be formed for reserving gas compressed under the predetermined rest liquid head pressure of the perfusate reservoir via the supplementary perfusate present in this supplementary perfusate reservoir. That is, the supplementary perfusate reservoir and the gas reservoir of the pressure-reduction compensating means may be readily formed by using such very simple construction. The preparation of the pressure-reduction compensating means may be performed quickly. Furthermore, in the attachment of the pressure-reduction compensating means to an existing system such as a system used for the ultrasonic emulsifying aspirating operation, as the branch-joint tube is provided in advance as being connected to the base end of the tube constituting the pressure-reduction compensating means, this attachment can be done easily by connecting this branch-joint tube to the inlet opening of the introduction tube of the handpiece. This readiness of the attachment will contribute to widespread use of the apparatus of the invention.